scripts/devtool: add development helper tool

Provides an easy means to work on developing applications and system
components with the build system.

For example to "modify" the source for an existing recipe:

  $ devtool modify -x pango /home/projects/pango
  Parsing recipes..done.
  NOTE: Fetching pango...
  NOTE: Unpacking...
  NOTE: Patching...
  NOTE: Source tree extracted to /home/projects/pango
  NOTE: Recipe pango now set up to build from /home/paul/projects/pango

The pango source is now extracted to /home/paul/projects/pango, managed
in git, with each patch as a commit, and a bbappend is created in the
workspace layer to use the source in /home/paul/projects/pango when
building.

Additionally, you can add a new piece of software:

  $ devtool add pv /home/projects/pv
  NOTE: Recipe /path/to/workspace/recipes/pv/pv.bb has been
  automatically created; further editing may be required to make it
  fully functional

The latter uses recipetool to create a skeleton recipe and again sets up
a bbappend to use the source in /home/projects/pv when building.

Having done a "devtool modify", can also write any changes to the
external git repository back as patches next to the recipe:

  $ devtool update-recipe mdadm
  Parsing recipes..done.
  NOTE: Removing patch mdadm-3.2.2_fix_for_x32.patch
  NOTE: Removing patch gcc-4.9.patch
  NOTE: Updating recipe mdadm_3.3.1.bb

[YOCTO #6561]
[YOCTO #6653]
[YOCTO #6656]

(From OE-Core rev: 716d9b1f304a12bab61b15e3ce526977c055f074)

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/lib/devtool/__init__.py

@@ -0,0 +1,78 @@
+#!/usr/bin/env python
+
+# Development tool - utility functions for plugins
+#
+# Copyright (C) 2014 Intel Corporation
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+
+import os
+import sys
+import subprocess
+import logging
+
+logger = logging.getLogger('devtool')
+
+def exec_build_env_command(init_path, builddir, cmd, watch=False, **options):
+    import bb
+    if not 'cwd' in options:
+        options["cwd"] = builddir
+    if init_path:
+        logger.debug('Executing command: "%s" using init path %s' % (cmd, init_path))
+        init_prefix = '. %s %s > /dev/null && ' % (init_path, builddir)
+    else:
+        logger.debug('Executing command "%s"' % cmd)
+        init_prefix = ''
+    if watch:
+        if sys.stdout.isatty():
+            # Fool bitbake into thinking it's outputting to a terminal (because it is, indirectly)
+            cmd = 'script -q -c "%s" /dev/null' % cmd
+        return exec_watch('%s%s' % (init_prefix, cmd), **options)
+    else:
+        return bb.process.run('%s%s' % (init_prefix, cmd), **options)
+
+def exec_watch(cmd, **options):
+    if isinstance(cmd, basestring) and not "shell" in options:
+        options["shell"] = True
+
+    process = subprocess.Popen(
+        cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, **options
+    )
+
+    buf = ''
+    while True:
+        out = process.stdout.read(1)
+        if out:
+            sys.stdout.write(out)
+            sys.stdout.flush()
+            buf += out
+        elif out == '' and process.poll() != None:
+            break
+    return buf
+
+def setup_tinfoil():
+    import scriptpath
+    bitbakepath = scriptpath.add_bitbake_lib_path()
+    if not bitbakepath:
+        logger.error("Unable to find bitbake by searching parent directory of this script or PATH")
+        sys.exit(1)
+
+    import bb.tinfoil
+    import logging
+    tinfoil = bb.tinfoil.Tinfoil()
+    tinfoil.prepare(False)
+    tinfoil.logger.setLevel(logging.WARNING)
+    return tinfoil
+